The research may be divided into two major categories: I. Studies on the solution structure of DNA and on the changes it undergoes upon interaction with ions, polyamines and proteins. More specifically, we will be studying: 1) the collapse of DNA in the presence of polyamines and polyamine homologs. Techniques used are flow linear dichroism, fiber diffraction techniques, quasi-elastic light scattering and circular dichroism. 2) Investigations of the effect of ion binding and intercalation on the flexibility and structure of DNA in solution. 3) Protein-DNA interaction. The main object is to use optical-hydrodynamic techniques such as streaming linear dichroism and quasielastic light scattering to elucidate the structural changes undergone by the DNA as a result of these interactions. Early systems to be studied are the higher structure of chromatin and single stranded DNA saturated with the gene 32 protein of phage T4. These studies will be accompanied by theoretical and spectroscopic investigations on the optical, mechanical and statistical properties of DNA. II. Studies of mutant T4 lysozymes. Temperature sensitive and other mutations of phage T4 lysozyme are to be studied in solution as a function of known point mutations. The aim is to elucidate the nature of the interactions which cause spontaneous folding. The work will include studies of the thermodynamics of stabilization. Since we now believe the temperature sensitivity may be connected with enhanced structural fluctuations rather than structural changes, we will be investigating this aspect by studying the sensitivity to proteolytic degradation and hydrogen exchange techniques.